[v10,01/11] util/cutils: Add qemu_strtotime_ps()

Commit Message

Tao Xu Sept. 1, 2019, 2:21 p.m. UTC

To convert strings with time suffixes to numbers, support time unit are
"ps" for picosecond, "ns" for nanosecond, "us" for microsecond, "ms"
for millisecond or "s" for second.

Signed-off-by: Tao Xu <[e-mail]>
---

New patch in v10.
---
 include/qemu/cutils.h |  1 +
 util/cutils.c         | 82 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+)

Patch

diff --git a/include/qemu/cutils.h b/include/qemu/cutils.h
index 12301340a4..0e70a807e1 100644
--- a/include/qemu/cutils.h
+++ b/include/qemu/cutils.h
@@ -180,5 +180,6 @@  int uleb128_decode_small(const uint8_t *in, uint32_t *n);
  * *str1 is <, == or > than *str2.
  */
 int qemu_pstrcmp0(const char **str1, const char **str2);
+int qemu_strtotime_ps(const char *nptr, const char **end, uint64_t *result);
 
 #endif
diff --git a/util/cutils.c b/util/cutils.c
index fd591cadf0..a50c15f46a 100644
--- a/util/cutils.c
+++ b/util/cutils.c
@@ -847,3 +847,85 @@  int qemu_pstrcmp0(const char **str1, const char **str2)
 {
     return g_strcmp0(*str1, *str2);
 }
+
+static int64_t timeunit_mul(const char *unitstr)
+{
+    if (g_strcmp0(unitstr, "ps") == 0) {
+        return 1;
+    } else if (g_strcmp0(unitstr, "ns") == 0) {
+        return 1000;
+    } else if (g_strcmp0(unitstr, "us") == 0) {
+        return 1000000;
+    } else if (g_strcmp0(unitstr, "ms") == 0) {
+        return 1000000000LL;
+    } else if (g_strcmp0(unitstr, "s") == 0) {
+        return 1000000000000LL;
+    } else {
+        return -1;
+    }
+}
+
+
+/*
+ * Convert string to time, support time unit are ps for picosecond,
+ * ns for nanosecond, us for microsecond, ms for millisecond or s for second.
+ * End pointer will be returned in *end, if not NULL. Return -ERANGE on
+ * overflow, and -EINVAL on other error.
+ */
+static int do_strtotime(const char *nptr, const char **end,
+                      const char *default_unit, uint64_t *result)
+{
+    int retval;
+    const char *endptr;
+    int mul_required = 0;
+    int64_t mul;
+    double val, integral, fraction;
+
+    retval = qemu_strtod_finite(nptr, &endptr, &val);
+    if (retval) {
+        goto out;
+    }
+    fraction = modf(val, &integral);
+    if (fraction != 0) {
+        mul_required = 1;
+    }
+
+    mul = timeunit_mul(endptr);
+
+    if (mul == 1000000000000LL) {
+        endptr++;
+    } else if (mul != -1) {
+        endptr += 2;
+    } else {
+        mul = timeunit_mul(default_unit);
+        assert(mul >= 0);
+    }
+    if (mul == 1 && mul_required) {
+        retval = -EINVAL;
+        goto out;
+    }
+    /*
+     * Values >= 0xfffffffffffffc00 overflow uint64_t after their trip
+     * through double (53 bits of precision).
+     */
+    if ((val * (double)mul >= 0xfffffffffffffc00) || val < 0) {
+        retval = -ERANGE;
+        goto out;
+    }
+    *result = val * (double)mul;
+    retval = 0;
+
+out:
+    if (end) {
+        *end = endptr;
+    } else if (*endptr) {
+        retval = -EINVAL;
+    }
+
+    return retval;
+}
+
+int qemu_strtotime_ps(const char *nptr, const char **end, uint64_t *result)
+{
+    return do_strtotime(nptr, end, "ps", result);
+}